The invention relates to a damper arrangement in a water heater. More specifically, the invention relates to a damper arrangement that uses an airflow apparatus to substantially reduce standby heat loss due to natural convection cycles in a water heater flue. It is known to use a damper in a water heater flue. Known dampers use a physical obstruction to close the flue during standby. One example of a physical obstruction type damper is disclosed in U.S. Pat. No. 4,953,510.
The invention provides a water heater comprising a water tank adapted to contain water, a combustion chamber beneath the water tank, a burner within the combustion chamber and operable to create products of combustion, and a flue extending substantially vertically through the water tank. The flue communicates with the combustion chamber to conduct the products of combustion from the combustion chamber and to transfer heat to water stored within the water tank. The water heater also includes an airflow apparatus capable of creating airflow in the absence of any opposition to the airflow. The airflow apparatus communicates with the flue and resists standby convection flow of flue gases out of the flue when the burner is not operating.
The airflow apparatus may include a fan or an ionic wind device. The airflow apparatus may be oriented to create a downdraft within the flue or an air curtain across the top of the flue. The downdraft creates a downwardly-directed pressure within the flue that countervails upwardly-directed pressure created by standby convection cycles in the flue. The air curtain creates a flow of air across the top of the flue, which flow of air resists the flow of flue gases out of the flue when the water heater is in standby mode.
The ionic wind device includes one or more first electrodes that are preferably over the top end of the flue. A second electrode, which may be a portion of the flue itself, is spaced from the first electrodes. A power supply is interconnected between the first electrodes and the second electrode to create a voltage difference therebetween. The first electrodes ionize the air, and the second electrode attracts the ions. The ions are therefore biased for movement toward the second electrode. In the absence of an opposition to such movement of the ions, a flow of air is created by the ions as they move from the first electrodes to the second electrode. When there are flue gases present in the flue, the ions bump into flue gas particles and resist the upward movement of the flue gases out of the flue.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.